WO2019188967A1

WO2019188967A1 - Surface-coated cutting tool

Info

Publication number: WO2019188967A1
Application number: PCT/JP2019/012475
Authority: WO
Inventors: 達貴木下; 達生橋本; 峻佐藤; 雄斗菅原; 拓哉前川
Original assignee: 三菱マテリアル株式会社
Priority date: 2018-03-27
Filing date: 2019-03-25
Publication date: 2019-10-03
Also published as: JPWO2019188967A1; US20210016361A1; EP3778080A4; CN111902231A; EP3778080A1; KR20200128060A

Abstract

This surface-coated cutting tool is provide with, on a tool base body (11) made of a tungsten carbide-based cemented carbide, a lower layer (2) and an upper layer (3), wherein the lower layer (2) includes: a W layer (4) formed extending from the surface of the tool base body (11) inward to a predetermined depth; a metal carbide layer (5) formed immediately above the W layer (4); and a metal carbon nitride layer (6) formed immediately above the metal carbide layer (5). The upper layer (3) has a structure in which A-layers and B-layers are alternately layered, each of the A-layers includes an (Al,Ti)N layer represented by (Al_xTi_1-x)N (where x represents an atom ratio satisfying 0.40≤x≤0.70), and each of the B-layers includes an (Al,Ti,Cr,Si,Y)N layer represented by (Al_1-a-b-c-dTi_aCr_bSi_cY_d)N (where a, b, c, and d represent atom ratios satisfying 0≤a≤0.40, 0.05≤b≤0.40, 0≤c≤0.20, and 0.01≤d≤0.10).

Description

Surface coated cutting tool

This invention shows excellent chipping resistance and wear resistance without causing peeling of the hard coating layer in high-speed cutting of Ni-base heat-resistant alloys, and excellent cutting performance over a long period of use. The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool).
This application claims priority on Japanese Patent Application No. 2018-059654 filed in Japan on March 27, 2018, the contents of which are incorporated herein by reference.

In general, as a coated tool, for throwing inserts that can be used detachably attached to the tip of a cutting tool for turning and planing of various materials such as steel and cast iron, and for drilling and cutting the work material Known drills and miniature drills, end mills used for chamfering and grooving, shoulder processing, etc. of the work material, solid hob, pinion cutter used for gear cutting of the tooth profile of the work material, etc. Yes.
Many proposals have been made for the purpose of improving the cutting performance of the coated tool.

For example, Patent Document 1 proposes a hard film having excellent wear resistance formed on the surface of a cutting tool for alloy steel and the like and a method for forming such a hard film. excellent as a hard film _{_{_{_{was, M a Cr b Al c Si}}}} d B e Y f Z made of a hard coating (where, M is excluded, periodic table group 4A elements, 5A group elements, the group 6A element (Cr) At least one element selected from the group consisting of N, CN, NO or CNO, a + b + c + d + e + f = 1, 0 <a ≦ 0.3, 0.05 ≦ b ≦ 0.4, 0.4 ≦ c ≦ 0.8, 0 ≦ d ≦ 0.2, 0 ≦ e ≦ 0.2, 0.01 ≦ f ≦ 0.1 (a, b, c, d, e and f are respectively Satisfying an atomic ratio of M, Cr, Al, Si, B and Y) has been proposed.

Further, Ti can be selected as M, and when M is Ti, c is 0.5 ≦ c ≦ 0.8, and f is 0.02 ≦ f ≦ 0.1. In addition, it is described that the hard coating can be alternately laminated with different compositions.
Further, after the hard coating is charged into the AIP apparatus, the substrate is cleaned under specific conditions (for example, pressure: 0.6 Pa, voltage: 500 V, time: 5 minutes) using Ar ions, It is described that a film can be formed by a cathode discharge type arc ion plating method.

Moreover, in patent document 2, in order to aim at the durability improvement of the coated cutting tool applied to cutting of steel, Ni-base heat-resistant alloy, etc., the base material, the intermediate film provided on the base material, and the intermediate film The intermediate coating has a nano-beam diffraction pattern indexed to the crystal structure of WC, is made of a carbide containing W and Ti, and has a film thickness. 1 nm or more and 10 nm or less, and the hard coating is a nitride or carbonitride having a face-centered cubic lattice structure, containing at least Al, Ti, and Y, and containing a metal element including a semimetal When the total ratio (atomic%) is 100%, the Al content ratio (atomic%) is 60% to 75%, the Ti content ratio (atomic%) is 20% to 35%, and the Y content ratio. (Atom%) is 1% or more and 5% or less Coated cutting tool has been proposed that.

In order to form the intermediate film, it is preferable to perform Ti bombardment using a cathode having a magnetic field configuration in which a coil magnet is provided on the outer periphery of the target to confine the arc spot inside the target. Further, as specific processing conditions, the negative bias voltage applied to the substrate is set to -1000 V to -700 V, the current supplied to the target is set to 80 A to 150 A, and the base before the bombarding process is performed. The heating temperature of the material is set to 450 ° C. or higher, the Ti bombarding process is performed for 3 to 7 minutes, and Ti bombarding may be performed while introducing argon gas, nitrogen gas, hydrogen gas, hydrocarbon gas, or the like. However, it is preferable to carry out the furnace atmosphere under a vacuum of 1.0 × 10 ⁻² Pa or less.

Further, in Patent Document 3, a WC-based cemented carbide is used as a base material for the purpose of improving the adhesion strength between the coating and the base material and improving the peel resistance and wear resistance in the cutting of alloy tool steel (SKD11). A coated tool and a manufacturing method thereof have been proposed.
According to the description in Patent Document 3, this coated tool has a W-modified phase (preferably having an average thickness of 10 to 300 nm) having a bcc crystal structure on the surface of a WC-based cemented carbide base material. The W-modified phase is W formed by the decomposition of W and C by irradiating one or more metals selected from Ti, Zr, Hf, Nb, and Ta by ion irradiation of the substrate. And having a carbide phase of one or more metals selected from Ti, Zr, Hf, Nb and Ta immediately above the W-modified phase, and a hard film (this hard film is preferably At least one layer is a nitride containing one or more elements selected from Ti, Cr, W, Nb, Y, Ce, Si, and B and Al).
And this coated tool can be manufactured by the 1st process of performing ion bombardment processing to a substrate, and the 2nd process of forming a hard coat, and the 1st process of performing the said ion bombardment process Applies a negative bias voltage of −1000 to −600 (V) to the substrate, and a pressure of 0.01 to 2 Pa, and a mixed gas of hydrogen gas and Ar or N ₂ (however, the hydrogen gas of the mixed gas) The cathode material (one or more metals selected from Ti, Zr, Hf, Nb and Ta) is evaporated from an arc discharge evaporation source using a volume ratio of 1 to 20%. The substrate is irradiated with metal ions evaporated from the substrate, thereby setting the surface temperature of the substrate in the range of 800 to 860 ° C., forming a W-modified phase having a crystal structure of bcc structure on the surface of the substrate, and Ti, just above the quality phase It is disclosed that a carbide phase of one or more metals selected from Zr, Hf, Nb, and Ta is formed, and a hard film is formed immediately above the carbide phase.

Japanese Patent No. 4713413 JP 2017-001147 A Japanese Patent No. 5098726

In recent years, the use of FA for cutting devices has been remarkable. On the other hand, there is a strong demand for labor saving and energy saving and further cost reduction for cutting, and with this trend, cutting tends to become faster and more efficient. At the same time, there is a tendency to demand a versatile cutting tool that can cut as many work materials as possible.
In the conventional coated tools shown in Patent Documents 1 and 3, when this is used for cutting alloy steel, there is no particular problem. For example, this is applied to Inconel 718 (registered trademark). When subjected to high-speed milling and high-speed drilling of typical Ni-base heat-resistant alloys, the adhesion between the tool base and the hard coating layer, despite the large thermal and mechanical loads acting on the cutting edge Is not enough. For this reason, abnormal damage such as peeling occurs, and due to this, the service life is reached in a short time.

In Patent Document 2, a cubic structure nitride layer or carbonitride layer containing at least Al, Ti, and Y is provided as the hard coating, and Ti bombardment is provided between the tool base and the hard coating. By providing the intermediate film formed by the treatment, it is said that the durability of the coated tool in the cutting work of Ni-base heat-resistant alloy or the like is enhanced. However, in high-speed milling and high-speed drilling of Ni-base heat-resistant alloys, cutting with large thermal and mechanical loads on the cutting edge does not provide sufficient adhesion between the intermediate coating and hard coating. For this reason, peeling is likely to occur, and due to this, the service life is reached in a relatively short time.

In view of the above, the present inventors, from the above-mentioned viewpoint, are accompanied by high heat generation such as high-speed milling processing and high-speed drilling processing such as Ni-base heat-resistant alloys, and a large thermal load on the cutting blade. A cutting tool with excellent welding resistance, chipping resistance, chipping resistance, peeling resistance, and excellent wear resistance over a long period of use under cutting conditions where mechanical loads are applied As a result of earnest research to develop, the following knowledge was obtained.

The inventors first investigated the applicability of Ni-base heat-resistant alloy as a cutting tool for the hard coating disclosed in Patent Document 1 proposed as a cutting tool for alloy steel. From the viewpoint of welding resistance, the composition _{_{formula: (Al 1-a-b}} -c-d Ti a Cr b Si c Y d) when expressed in N, 0 ≦ a ≦ 0.40,0.05 ≦ b ≦ 0.40, 0 ≦ c ≦ 0.20, 0.01 ≦ d ≦ 0.10 (however, a, b, c, and d are atomic ratios) having an average composition (hereinafter referred to as a hard coating layer) , "(Al, Ti, Cr, Si, Y) N layer" may be suitable from the viewpoint of welding resistance in high-speed cutting of a Ni-base heat-resistant alloy. It was.
That is, in the above-mentioned coated tool, in particular, the Y component contained in the hard coating layer generates a stable oxide on the outermost surface of the hard coating layer, and this oxide improves the welding resistance. , Y component is present uniformly in the hard coating layer. For this reason, even when the cutting process proceeds, an oxide of Y always exists on the outermost surface of the hard coating layer, so that the welding resistance does not deteriorate.
However, when the layer thickness of the (Al, Ti, Cr, Si, Y) N layer is excessively increased, the life of the coated tool is shortened due to occurrence of chipping, chipping, peeling, and the like.

Therefore, the present inventors provide the hard coating layer with the above (Al, Ti, Cr) in order to provide a coated tool that exhibits excellent wear resistance over a long period of use without occurrence of chipping, chipping or peeling. , Si, Y) N layers and an Al and Ti composite nitride layer (hereinafter sometimes referred to as “(Al, Ti) N layer”). Further, the surface of the tool base was subjected to bombarding taught by

Patent Documents

2 and 3, and then a hard coating layer composed of the alternately laminated structure was formed. The occurrence of defects was suppressed and the tool life was extended to some extent. However, it was not possible to suppress the occurrence of peeling, and it could not be said that the tool characteristics were still sufficiently satisfactory.

The inventors of the present invention have further studied the bombardment process described in

Patent Documents

2 and 3 and changed the metal ion bombardment process conditions to have a layer structure different from that described in

Patent Documents

2 and 3. It was found that the effect of improving the adhesion between the hard coating layer and the tool base can be remarkably improved by forming the lower layer and forming the hard coating layer via the lower layer. As a result, in high-speed cutting of a Ni-base heat-resistant alloy, it is possible to suppress the occurrence of delamination, and at the same time, to suppress the occurrence of abnormal damage such as welding, chipping, and defects. It was found that a coated tool exhibiting excellent wear resistance can be obtained.
That is, the present inventors set the treatment atmosphere to 1 × 10 ⁻ when ion bombarding any one kind of metal selected from Ti, Cr, Zr, Hf, Nb and Ta as the metal ion bombardment for the tool base. A high vacuum of ³ Pa or less was set, the processing temperature of the tool base was increased to about 750 to 800 ° C., and the processing time was increased (for example, 30 minutes to 60 minutes). Thus, a lower layer different from the lower layers described in

Patent Documents

2 and 3, specifically, a W layer (tungsten layer), a metal carbide layer formed immediately above the layer, and the metal It has been found that the adhesion between the hard coating layer and the tool base can be improved by forming a lower layer made of a metal carbonitride layer formed immediately above the carbide layer.

Further, by forming such a lower layer between the hard coating layer and the tool base, a Ni base that generates high heat and exerts a large thermal load and mechanical load on the cutting edge. In high-speed cutting of heat-resistant alloys, it is possible to suppress the occurrence of delamination, and further suppress the occurrence of abnormal damage such as welding, chipping and chipping, and obtain a coated tool that exhibits excellent cutting performance over a long period of use. Was found.

The present invention has been made based on the above knowledge, and the surface-coated cutting tool according to the present invention has the following configurations (1) to (3).
(1) A surface-coated cutting tool in which a lower layer is provided on a tool base made of a tungsten carbide-based cemented carbide and an upper layer of an alternately laminated structure is provided on the surface of the lower layer, (a) to (g) It has the characteristics of.
(A) The lower layer includes a W layer, a metal carbide layer, and a metal carbonitride layer.
(B) The W layer is formed from the surface of the tool base to the inside thereof over a depth of 10 to 500 nm.
(C) The metal carbide layer is any one metal carbide layer selected from Ti, Cr, Zr, Hf, Nb and Ta, and has an average layer thickness of 5 to 500 nm, It is formed directly above.
(D) The metal carbonitride layer is a metal carbonitride layer containing a metal component contained in the metal carbide layer, has an average layer thickness of 5 to 300 nm, and is directly above the metal carbide layer. It is formed.
(E) The upper layer has an alternate laminated structure in which at least one A layer and B layer are alternately laminated, and has a total average layer thickness of 1.0 to 8.0 μm.
(F) The A layer is a composite nitride layer of Al and Ti having a _single layer average thickness of 0.1 to 5.0 μm, and its composition is expressed by a composition formula: (Al _x Ti _1-x ) N The average composition satisfies 0.40 ≦ x ≦ 0.70 (where x is an atomic ratio).
(G) The B layer is a composite nitride layer of Al, Ti, Cr, Si, and Y having a _single layer average thickness of 0.1 to 5.0 μm, and the composition is expressed by a composition formula: (Al ₁ when expressed in _{_{_{-a-b-c-d Ti}}} a Cr b Si c Y d) N, 0 ≦ a ≦ 0.40,0.05 ≦ b ≦ 0.40,0 ≦ c ≦ 0.20,0 .01 ≦ d ≦ 0.10 (where a, b, c and d are all atomic ratios).
(2) The surface-coated cutting tool according to (1), wherein the surface-coated cutting tool is any one of a surface-coated insert, a surface-coated end mill, and a surface-coated drill.
(3) A surface-coated cutting tool for Ni-base heat-resistant alloy high-speed cutting, comprising the surface-coated cutting tool described in (1) or (2).

The coated tool of the present invention includes a lower layer and an upper layer, and the lower layer is formed from a tool base surface to a predetermined depth inside thereof, and a metal carbide layer formed on the surface of the W layer. And a metal carbonitride layer formed on the surface of the metal carbide layer, and the upper layer is an A layer composed of an (Al, Ti) N layer and an (Al, Ti, Cr, Si, Y) N layer The B layer is composed of an alternately laminated structure in which at least one B layer is alternately laminated, and the adhesion strength between the tool base and the upper layer is increased by the lower layer interposed between the tool base and the upper layer. At the same time, the upper layer has excellent welding resistance, chipping resistance, chipping resistance, and wear resistance.
Therefore, the coated tool of the present invention suppresses the occurrence of delamination in high-speed cutting of a Ni-base heat-resistant alloy that is accompanied by high heat generation and a large thermal load and mechanical load acts on the cutting edge. It suppresses the occurrence of abnormal damage such as welding, chipping and chipping, and exhibits excellent cutting performance over a long period of use.

An example of the schematic longitudinal cross-sectional schematic diagram of the coating tool which concerns on one Embodiment is shown. 1 shows an example of a schematic plan view of an arc ion plating apparatus (not shown for a metal target for metal ion bombardment) used to form an upper layer of a coated tool according to an embodiment. 1 shows an example of a schematic front view of an arc ion plating apparatus (not shown for a metal target for metal ion bombardment) used to form an upper layer of a coated tool according to an embodiment.

FIG. 1 is a schematic longitudinal cross-sectional schematic diagram of a surface-coated tool according to this embodiment.
As shown in FIG. 1, in the coated tool according to the present embodiment, a lower layer 2 and an upper layer 3 having an alternately laminated structure are formed on a tool base 11 made of a tungsten carbide base cemented carbide.
The lower layer 2 includes a W layer 4, a metal carbide layer 5, and a metal carbonitride layer 6, but the W layer 4 is not formed on the surface of the tool base 11, but the tool base 11. It is formed over an average depth of 10 to 500 nm from the surface to the inside.
The metal carbide layer 5 is formed with an average layer thickness of 5 to 500 nm immediately above the W layer 4, and the metal carbonitride layer 6 is 5 to 500 nm directly above the metal carbide layer 5. It is formed with an average layer thickness of 300 nm. And, on the surface of the lower layer 2 composed of the W layer 4, the metal carbide layer 5, and the metal carbonitride layer 6, it has an alternately laminated structure in which the A layer and the B layer are alternately laminated. An upper layer 3 having a total average layer thickness of 1.0 to 8.0 μm is formed.

[Measurement method of average layer thickness]
The layer thickness is measured by cutting out a longitudinal section using a focused ion beam (FIB) and using an energy dispersive X-ray analysis method using a scanning electron microscope (SEM) or a transmission electron microscope (TEM) ( EDS), Auger Electron Spectroscopy (AES) or electron probe microanalyzer (EPMA) is used for cross-sectional measurement. The method for obtaining the layer thickness of each of the upper layers will be specifically described as follows. A line analysis of the composition with respect to the normal direction of the substrate surface is performed on the longitudinal section of the tool. Based on the component content change curve thus obtained, the boundary between the A layer and the B layer is defined as an increase start position and a decrease start position of the Cr content in the B layer. Accordingly, the layer thickness of the A layer is from the Cr content decrease start position to the Cr content increase start position, and the B layer thickness is from the Cr content increase start position to the Cr content decrease start position. As a standard. The average layer thickness means an average value calculated by performing the measurement method five times.

2A and 2B show an arc ion plating (hereinafter referred to as “AIP”) apparatus 10 for forming the layer structure of the surface-coated tool according to the present embodiment (note that metal for metal ion bombardment treatment). The target is not shown). The lower layer 2 comprising the W layer 4, the metal carbide layer 5, and the metal carbonitride layer 6 by performing metal ion bombardment on the surface of the tool base 11 disposed on the rotary table of the AIP apparatus 10 under predetermined conditions. After that, the A layer and the B layer are alternately laminated to form the upper layer 3, and the surface-coated cutting tool according to this embodiment having a layer structure can be manufactured.

[Lower layer]
Both the W layer 4 and the metal carbide layer 5 constituting the lower layer 2 are layers formed by metal ion bombardment.

Among the layers constituting the lower layer 2, the W layer 4 and the metal carbide layer 5 immediately above the W layer 4 are decomposed into W and C in the vicinity of the surface of the tool base 11 by metal ion bombardment (irradiation). Thereby, the W layer 4 is formed from the surface of the tool base 11 to a predetermined depth, and the ion bombarded metal reacts with C on the surface of the W layer 4 to thereby form the metal carbide layer 5. Produces.

Here, if the average thickness (depth) of the W layer 4 to be formed is less than 10 nm, the metal carbide layer 5 immediately above is not sufficiently formed, and sufficient adhesion strength with the hard layer cannot be obtained. On the other hand, if the average thickness exceeds 500 nm, the hard coating layer is easily peeled off due to the embrittlement of the surface of the tool base 11, and therefore the W layer 4 formed from the surface of the tool base 11 toward the inside thereof. The average thickness (depth) is 10 to 500 nm or less. More preferably, it is 20 nm to 300 nm.

The metal carbide layer 5 formed immediately above the W layer 4 is formed by the reaction of bombarded metal ions with C decomposed from WC into W and C as described above. If the layer thickness is less than 5 nm, the thickness of the W layer 4 is too thin and the effect of improving the adhesion with the hard layer is small. On the other hand, if the average layer thickness exceeds 500 nm, the average thickness of the W layer 4 ( Since the depth) exceeds 500 nm, the surface of the tool base 11 becomes brittle. Therefore, the average thickness of metal carbide layer 5 formed immediately above W layer 4 is set to 5 to 500 nm. More preferably, it is 10 nm to 300 nm.

[Measurement method of average thickness (depth) of W layer]
The thickness (depth) of the W layer is measured by cutting a longitudinal section using a focused ion beam (FIB) and energy using a scanning electron microscope (SEM) or a transmission electron microscope (TEM). This is performed by cross-sectional measurement using a distributed X-ray analysis method (EDS), Auger Electron Spectroscopy (AES), or an electron probe microanalyzer (EPMA). A specific method for obtaining the thickness (depth) of the W layer is as follows. A line analysis of the composition with respect to the normal direction of the substrate surface is performed on the longitudinal section of the tool. The boundary of each layer is defined according to the following based on the component content change curve thus obtained. First, the boundary between the WC and the W layer is set as a W content increase start position. Further, the boundary between the W layer and the metal carbide layer is defined as an intersection of a curve indicating a change in the W content and a curve indicating a change in the content of the metal component constituting the metal carbide layer. From these, the thickness (depth) of the W layer is an intersection of the W content increase start position and the curve indicating the change in the W content and the curve indicating the change in the content of the metal component constituting the metal carbide layer. Required as a standard. The average thickness of the W layer refers to an average value calculated by performing the measurement method five times.

[Measuring method of average thickness of metal carbide layer]
The thickness of the metal carbide layer is measured by cutting a longitudinal section using a focused ion beam (FIB) and using an energy dispersive X using a scanning electron microscope (SEM) or a transmission electron microscope (TEM). It is performed by cross-sectional measurement using a line analysis method (EDS), Auger Electron Spectroscopy (AES), or an electron probe microanalyzer (EPMA). A specific method for obtaining the thickness of the metal carbide layer is as follows. A line analysis of the composition with respect to the normal direction of the substrate surface is performed on the longitudinal section of the tool. The boundary of each layer is defined according to the following based on the component content change curve thus obtained. First, the boundary between the W layer and the metal carbide layer is defined as an intersection of a curve indicating a change in the W content and a curve indicating a change in the content of the metal component constituting the metal carbide layer. Further, the boundary between the metal carbide layer and the metal carbonitride layer is set as the increase start position of the N content. From these, the thickness of the metal carbide layer is based on the intersection of the curve showing the change in the W content and the curve showing the change in the content of the metal component constituting the metal carbide layer and the increase start position of the N content. Desired. The average thickness of the metal carbide layer refers to an average value calculated by performing the measurement method five times.

[Measuring method of average thickness of metal carbonitride layer]
The thickness of the metal carbonitride layer is measured by cutting a longitudinal section using a focused ion beam (FIB), and energy dispersion using a scanning electron microscope (SEM) or a transmission electron microscope (TEM). This is performed by cross-sectional measurement using a type X-ray analysis method (EDS), Auger Electron Spectroscopy (AES), or an electron probe microanalyzer (EPMA). The method for obtaining the thickness of the metal carbonitride layer will be specifically described as follows. A line analysis of the composition with respect to the normal direction of the substrate surface is performed on the longitudinal section of the tool. The boundary of each layer is defined according to the following based on the component content change curve thus obtained. First, the boundary between the metal carbide layer and the metal carbonitride layer is set as the increase start position of the N content. Further, the boundary between the metal carbonitride layer and the upper layer is defined as the intersection of the metal component constituting the metal carbonitride layer and the curve indicating the change in the content of the metal component constituting the upper layer. From these, the thickness of the metal carbonitride layer is the intersection of the starting position of the increase of the N content and the curve indicating the change in the content of the metal component constituting the metal carbonitride layer and the metal component constituting the upper layer. As a standard. The average thickness of the metal carbonitride layer refers to an average value calculated by performing the measurement method five times.

In addition, a metal carbonitride layer 6 is formed on the surface of the metal carbide layer 5. This metal carbonitride layer 6 is formed when the upper layer 3 is formed by vapor deposition after the metal ion bombardment process. Is a layer. After the metal ion bombardment treatment is performed for a long time (30 to 60 minutes) under a high vacuum and the W layer 4 and the metal carbide layer 5 are formed, the upper layer 3 is further formed by vapor deposition in a nitrogen atmosphere. A metal carbonitride layer 6 can be formed. By this forming method, the metal carbonitride layer 6 including the metal component contained in the metal carbide layer 5 is obtained.

The metal carbonitride layer 6 is excellent in adhesion strength with the metal carbide layer 5 and at the same time is composed of a hard layer formed on the surface of the metal carbonitride layer 6, in particular, a composite nitride layer of Al and Ti. Excellent adhesion to the A layer. For this reason, the generation of delamination of the hard layer is suppressed in the high-speed cutting of the Ni-base heat-resistant alloy that is accompanied by the generation of high heat and that places a large thermal load and mechanical load on the cutting edge. However, when the average layer thickness of the metal carbonitride layer 6 is less than 5 nm, the adhesiveness between the metal carbide layer 5 and the A layer is not sufficiently exhibited, and when the average layer thickness exceeds 300 nm, Increases the distortion of the film, which leads to a decrease in adhesion. Therefore, the average thickness of the metal carbonitride layer 6 is set to 5 to 300 nm. More preferably, it is 10 to 200 nm.

[Formation of lower layer]
More specifically, an example of a method of forming the lower layer 2 is as follows.
First, the tool base 11 is placed on a turntable 12 in the AIP apparatus 10 so as to be able to rotate, and the inside of the apparatus is maintained at a high vacuum of 1 × 10 ⁻³ Pa or less, and the temperature of the tool base 11 is about 500 ° C. Then, the temperature of the tool base 11 is increased to about 750 to 800 ° C. so that this temperature is maintained during the metal ion bombardment process, and then a bias voltage of about −1000 V is applied to the tool base 11 to An ion bombarding target (for example, a Ti target) is supplied with an arc current of about 100 A, and this treatment is continued for about 30 to 60 minutes to carry out a metal ion bombardment treatment. The W layer 4 is formed to a depth, and at the same time, a metal carbide layer 5 having a predetermined thickness is formed on the surface of the W layer 4. Further, when the upper layer 3 is deposited, the upper layer 3 and the gold A metal carbonitride layer 6 is formed by a diffusion reaction between the metal carbide layers 5.
By the above method, the lower layer 2 including the W layer 4 having a predetermined depth, the metal carbide layer 5 having a predetermined average layer thickness, and the metal carbonitride layer 6 having a predetermined average layer thickness can be formed on the tool base 11.

The W layer 4, the metal carbide layer 5, and the metal carbonitride layer 6 are preferably formed in layers on the tool base 11. For example, the W layer 4, the metal carbide layer 5, and the metal carbonitride layer 6 may be formed in an island shape preferentially on the WC particles. In this case, the effect of improving the adhesion strength between the substrate and the hard coating layer can be obtained.

As a kind of metal which comprises the said metal carbide layer 5, any one metal selected from Ti, Cr, Zr, Hf, Nb, and Ta is suitable, and especially Ti and Cr are preferable.
When the metal composing the metal carbide layer 5 is ion bombarded, each metal is more likely to form a carbide than W, and therefore reacts with C decomposed into W and C in the vicinity of the surface of the tool base 11, As a result, the metal carbide layer 5 is formed on the surface of the W layer 4.

In addition, the metal carbonitride layer 6 is a carbonitride layer containing a metal component contained in the metal carbide layer 5, and the types of metals constituting the metal carbonitride layer 6 include Al, Ti, At least one metal selected from Cr, Zr, Hf, Nb and Ta is preferred, and Ti and Cr are particularly preferred.
Since the metal carbonitride layer 6 is formed, the lattice mismatch at the interface with the upper layer 3 is alleviated, so that the adhesion strength with the upper layer 3 is improved.

The ratio of carbon to nitrogen in the metal carbonitride layer 6 is not limited, but preferably the ratio of the atomic concentration of nitrogen to the total atomic concentration of carbon and nitrogen is 0 on average in the metal carbonitride layer 6. 0.1 to 0.9, and more preferably 0.1 to 0.6.

Since the metal constituting the metal carbide layer 5 and the metal constituting the metal carbonitride layer 6 are the same type of metal (for example, Ti carbide layer and Ti carbonitride layer), metal ion bombardment treatment and metal carbon There is an advantage that the nitride layer forming process can be performed continuously.
However, the metal is not limited to the same type of metal, and different types of metals can be used. In the metal ion bombardment process of the present invention, W particles may partially remain in the layer during the reaction process when forming the lower layer 2, but even in this case, the effect of improving the adhesion of the lower layer 2 Is demonstrated.

[Upper layer]
The upper layer 3 formed on the lower layer 2 has an alternately laminated structure in which at least one A layer and B layer are alternately laminated, and has a total average layer thickness of 1.0 to 8.0 μm. .
The layer A is a composite nitride layer of Al and Ti (hereinafter, also referred to as “(Al, Ti) N”) having an average layer thickness of 0.1 to 5.0 μm, and its composition Is represented by the composition formula: (Al _x Ti _1-x ) N, it has an average composition satisfying 0.40 ≦ x ≦ 0.70 (where x is an atomic ratio).
The layer B is a composite nitride (“(Al, Ti, Cr, Si, Y) N”) layer of Al, Ti, Cr, Si, and Y having an average layer thickness of 0.1 to 5.0 μm. Te, its composition, the composition _{_{formula: (Al 1-a-b}} -c-d Ti a Cr b Si c Y d) when expressed in N, 0 ≦ a ≦ 0.40,0.05 ≦ b ≦ 0 .40, 0 ≦ c ≦ 0.20, 0.01 ≦ d ≦ 0.10 (where a, b, c, and d are atomic ratios).

The value of N / (Ti + Al + N) in the composition formula regarding the A layer and the value of N / ((Al + Ti + Cr + Si + Y + N) in the composition formula regarding the B layer are not necessarily 0.5 of the stoichiometric ratio. Excluding elements such as carbon and oxygen that are inevitably detected due to the influence of contamination on the surface of the tool base 11, the atomic ratio of the content ratio of Ti, Al, N is quantified, and Al, Ti, Cr, Si N / (Ti + Al + N) or N / ((Al + Ti + Cr + Si + Y + N) is in the range of 0.45 or more and 0.65 or less. Since an effect equivalent to that of the A layer or the B layer having a ratio of 0.5 is obtained, there is no particular problem.

[(Al, Ti) N layer constituting upper layer A]
When the average layer thickness of the A layer composed of the (Al, Ti) N layer is less than 0.1 μm, the wear resistance improvement effect and the fracture resistance improvement effect are not sufficient, whereas the average layer If the thickness exceeds 5.0 μm, the internal strain of the A layer increases and it tends to self-destruct, so the average layer thickness of the A layer is 0.1 to 5.0 μm.
In addition, in the composition formula of the A layer: (Al _x Ti _1-x ) N, when the value of x indicating the average composition of Al is less than 0.40, the metal carbonitride layer 6 of the lower layer 2 and the A While the adhesion strength with the layer and the adhesion strength between the A layer and the B layer are increased, the high temperature hardness and high temperature oxidation resistance of the A layer are lowered. On the other hand, when the value of x exceeds 0.70, crystal grains having a hexagonal crystal structure are likely to be formed, and the hardness of the A layer is lowered, so that sufficient wear resistance cannot be obtained.
Therefore, the value x indicating the average composition of Al is set to 0.40 ≦ x ≦ 0.70.
The value x indicating the average composition of Al is more preferably 0.50 ≦ x ≦ 0.70.

The average composition x of the Al component in the A layer is obtained by measuring the amount of Al component at a plurality of locations (for example, 5 locations) in the longitudinal section of the A layer using SEM-EDS and averaging the measured values. Can do.
As for a plurality of locations in the longitudinal section, at least 5 locations are selected so that the distance between each location is 100 nm to 200 nm from one location selected at random.

[The upper layer B layer (Al, Ti, Cr, Si, Y) N layer]
The Al component in the (Al, Ti, Cr, Si, Y) N layer constituting the B layer of the upper layer 3 has the effect of improving the high temperature hardness and heat resistance, and the Ti component has the effect of improving the high temperature hardness. In addition to improving the high temperature toughness and high temperature strength of the component, the high temperature oxidation resistance is improved in the state where Al and Cr coexist, and the Si component has the effect of improving the heat plastic deformation property. As described above, the component has the effect of increasing the resistance to welding and at the same time increasing the resistance to oxidation.

When the a value (atomic ratio) indicating the Ti content in the total amount of Al, Ti, Cr, Si, and Y in the (Al, Ti, Cr, Si, Y) N layer exceeds 0.40, Since the durability of the coated tool decreases due to a significant decrease in the Al content, the a value is determined to be 0 to 0.40.

If the b value (atomic ratio) indicating the Cr content in the (Al, Ti, Cr, Si, Y) N layer is less than 0.05, the minimum required high temperature toughness and high temperature strength can be secured. Therefore, the occurrence of chipping and defects cannot be suppressed. On the other hand, if the b value exceeds 0.40, the progress of wear is promoted by the decrease in the relative Al content, so the b value is It is determined as 0.05 to 0.40.

When the c value (atomic ratio) indicating the content ratio of Si in the (Al, Ti, Cr, Si, Y) N layer exceeds 0.20, the improvement in heat-resistant plastic deformation is saturated, while the wear resistance is improved. Since the effect tends to decrease, the c value is set to 0 to 0.20.

If the d value (atomic ratio) indicating the Y content in the (Al, Ti, Cr, Si, Y) N layer is less than 0.01, the effect of improving the welding resistance and oxidation resistance can be expected. On the other hand, if the d value exceeds 0.10, AlN having a hexagonal crystal structure is generated, and the hardness of the B layer is lowered. Therefore, the d value is determined to be 0.01 to 0.10. .

Desirable ranges for a, b, c, and d are 0 ≦ a ≦ 0.30, 0.10 ≦ b ≦ 0.30, 0.05 ≦ c ≦ 0.15, 0.05 ≦ d ≦ 0. 08.

The B layer composed of the (Al, Ti, Cr, Si, Y) N layer cannot exhibit excellent wear resistance over a long period of use if its average layer thickness is less than 0.1 μm. If the average layer thickness exceeds 5.0 μm, chipping and defects are likely to occur. Therefore, the average layer thickness of the B layer made of the (Al, Ti, Cr, Si, Y) N layer is 0. It was determined to be 1 to 5.0 μm. The average composition a, b, c, d of each of the Ti component, Cr component, Si component and Y component in the B layer is determined by using SEM-EDS at a plurality of locations (for example, 5 locations) in the longitudinal section of the B layer. ) By measuring the amount of each component and averaging the measured values.

[Total average layer thickness of upper layer]
As described above, the single layer average layer thickness of the A layer and the single layer average layer thickness of the B layer are 0.1 to 5.0 μm, respectively, but a stack in which the A layer and the B layer are alternately stacked. The total average layer thickness of the upper layer 3 of the structure is 1.0 to 8.0 μm. The single layer average layer thickness of the A layer and the single layer average layer thickness of the B layer are more preferably 0.5 to 4.0 μm, respectively.
This is because if the total average layer thickness of the upper layer 3 is less than 1.0 μm, it cannot exhibit excellent wear resistance over a long period of use, while if the total average layer thickness exceeds 8.0 μm, This is because the layer 3 is likely to cause abnormal damage such as chipping, chipping, and peeling.

The A layer and the B layer preferably have a stacked structure in which at least one layer is alternately stacked.
When the upper layer 3 is formed on the surface of the lower layer 2, the adhesion strength between the A layer and the metal carbonitride layer 6 of the lower layer 2 is high, and the adhesion strength between the A layer and the B layer is also high. Therefore, it is desirable to provide the A layer of the upper layer 3 immediately above the metal carbonitride layer 6 of the lower layer 2.

The surface-coated cutting tool is preferably any one of a surface-coated insert, a surface-coated end mill, and a surface-coated drill.
The surface-coated cutting tool is preferably for Ni-base heat-resistant alloy high-speed cutting.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1
As raw material powders, WC powder, TiC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder and Co powder all having an average particle diameter of 0.5 to 5 μm are prepared. 1 was added to the compounding composition shown in FIG. 1, and after adding wax, ball milled in acetone for 24 hours, dried under reduced pressure, and then pressed into a green compact of a predetermined shape at a pressure of 98 MPa. The insert shape specified in ISO / CNMG120408 is formed by vacuum sintering in a vacuum of 1370 to 1470 ° C. under a condition of holding for 1 hour at a predetermined temperature, and after the sintering, the cutting edge is subjected to honing. Tool bases 11 (inserts) 1 to 4 made of WC-based cemented carbide were prepared.

A lower layer and an upper layer are formed on the tool base 11 (inserts) 1 to 4 in the following steps, and the surface-coated inserts 1 to 8 (hereinafter referred to as the present tool 1 to 8) of the present invention are respectively formed. Manufactured.
Step (a):
Each of the tool bases 1 to 4 is ultrasonically cleaned in acetone and dried, and is separated from the central axis on the rotary table of the AIP apparatus 10 shown in FIGS. 2A and 2B by a predetermined distance in the radial direction. A target 13 (cathode electrode) made of an Al—Ti alloy having a predetermined composition is placed on one side of the AIP apparatus 10 and an Al—Ti—Cr—Si—Y alloy having a predetermined composition is placed on the other side. A target 14 (cathode electrode) made of
Step (b):
First, the tool base 11 that rotates while rotating on the rotary table while the inside of the apparatus is evacuated and kept in a vacuum (1 × 10 ⁻³ Pa or less) is heated from about 500 ° C. to a predetermined temperature (shown in Table 2). The tool substrate is heated in sequence to a metal ion bombardment tool temperature, and a bias voltage shown in Table 2 is applied to the tool substrate 11 between the tool substrate 11 and a metal ion bombardment target (for example, Ti). The lower layer 2 shown in Table 4 is formed by applying the metal ion bombarding to the tool base 11 by applying the arc current shown in Table 2 and the processing time shown in Table 2 as well.
Step (c):
Next, nitrogen gas is introduced as a reaction gas into the apparatus to obtain the nitrogen partial pressure shown in Table 3, and the temperature of the tool base 11 that rotates while rotating on the rotary table 12 falls within the temperature range shown in Table 3. In addition, a DC bias voltage shown in Table 3 was applied, and a current of 150 A was applied between the Al—Ti alloy target 13 and the anode electrode 15 to generate an arc discharge. And depositing an A layer having the composition and average layer thickness shown in Table 4;
Step (d):
Next, nitrogen gas is introduced as a reaction gas into the apparatus from the reaction gas inlet (20) to obtain the nitrogen partial pressure shown in Table 3, and the temperature of the tool base 11 rotating while rotating on the rotary table 12 is adjusted. While maintaining the temperature range shown in Table 3 and applying the DC bias voltage shown in Table 3, a current of 150 A was passed between the Al—Ti—Cr—Si—Y alloy target 14 and the anode electrode 16. An arc discharge was generated, and a B layer having the composition shown in Table 4 and an average layer thickness was formed on the surface of the tool base 11 by vapor deposition.
Step (e):
Then, (c) and (d) were repeated until the total average layer thickness of the upper layer was reached.
The tools 1 to 8 of the present invention shown in Table 4 were produced by the above steps (a) to (e), respectively.

Comparative example:
For comparison purposes, each of the WC-base cemented carbide tool bases 11 (inserts) 1 to 4 produced in Example 1 was ultrasonically cleaned in acetone and dried, as shown in FIGS. 2A and 2B. The AIP device 10 shown is mounted along the outer peripheral portion at a position that is a predetermined distance in the radial direction from the central axis on the rotary table shown in FIG. The surface-coated inserts 1 to 6 of the comparative examples shown in Table 7 (hereinafter referred to as comparative example tools 1 to 6) were manufactured respectively.
Specifically, it is as follows.
As for Comparative Example Tools 1 to 4, as shown in Comparative Example Conditions 1 to 4 in Table 5, while maintaining the inside of the AIP apparatus 10 in the furnace atmosphere and furnace pressure shown in Table 5, the tool base 11 is heated with a heater. Is heated to the temperature shown in Table 5 and then the DC bias voltage shown in Table 5 is applied to the tool base 11 rotating while rotating on the rotary table 12, and the metal ion bombardment target and the anode electrode are applied. The arc current shown in Table 5 was passed to generate an arc discharge, and the tool base 11 surface was bombarded.
In addition, the

comparative tools

5 and 6 were subjected to bombardment processing as shown in

comparative example conditions

5 and 6 in Table 5, but the processing of comparative example condition 5 was within the range disclosed in Patent Document 2. In addition, the process of Comparative Example Condition 6 is a condition within the range disclosed in Patent Document 3. Table 6 shows the film formation conditions of the upper layer after the bombarding of the comparative tools 1 to 4 and the

comparative tools

5 and 6.

With respect to the inventive tools 1 to 8 and comparative tools 1 to 6 produced above, a longitudinal section is cut out using a focused ion beam (FIB), and a scanning electron microscope (SEM) or a transmission electron microscope ( The upper layer is measured by cross-section measurement using energy dispersive X-ray analysis (EDS) using TEM, Auger Electron Spectroscopy (AES), or Electron Probe Micro Analyzer (EPMA). The component composition of layer A and layer B and the thickness of each layer were measured at five locations, and the average composition and average layer thickness were calculated from the average values.
In the lower W layer, the metal carbide layer, and the metal carbonitride layer, the identification of each layer and the thickness of each layer were calculated by average cross-section measurement using the same analysis method as that for the upper layer. The method for obtaining the layer thickness of each lower layer was specifically described as follows. A line analysis of the composition with respect to the normal direction of the substrate surface was performed on the longitudinal section of the tool. The boundary of each layer was defined according to the following based on the component content change curve thus obtained. First, the boundary between the WC and the W layer was set as the W content increase start position. In addition, the boundary between the W layer and the metal carbide layer was defined as the intersection of a curve indicating the change in the W content and a curve indicating the change in the content of the metal component constituting the metal carbide layer. Furthermore, the boundary between the metal carbide layer and the metal carbonitride layer was set as the increase start position of the N content. And the boundary of a metal carbonitride layer and an upper layer was made into the intersection of the curve which shows the content change of the metal component which comprises a metal carbonitride layer, and the metal component which comprises an upper layer. From this, the depth of the W layer, the layer thickness of the metal carbide layer, and the layer thickness of the metal carbonitride layer were determined on the basis of the W content, the N content increase start position, or the intersection of each curve.
And this measurement was repeated in five places in the longitudinal section of a tool, and the average value was made into the average layer thickness of each layer of a lower layer.
Tables 4 and 7 show the measured and calculated values.

Next, the tools 1 to 8 of the present invention and the comparative tools 1 to 6 are all in accordance with the following conditions (referred to as cutting conditions 1) in a state where they are screwed to the tip of the tool steel tool with a fixing jig. A wet continuous cutting test of a Ni-base heat-resistant alloy was performed, and the flank wear width of the cutting edge was measured.
<Cutting condition 1>
Work material: Ni-based heat-resistant alloy (Cr 19 mass%-Fe 19 mass%-Mo 3 mass%-Ti 0.9 mass%-Al 0.5 mass%-Ni balance) round bar,
Cutting speed: 100 m / min. ,
Cutting depth: 0.5 mm,
Feed: 0.15 mm / rev. ,
Cutting time: 10 minutes,
Cutting oil: water-soluble coolant Table 8 shows the results.

Example 2
The raw material powder having the composition shown in Table 1 is sintered under the conditions shown in Example 1 to form a round tool sintered body for forming a tool base having a diameter of 10 mm. Further, from the round bar sintered body, Tool base 11 (end mill) 1 to 4 made of a WC-base cemented carbide having a 4-blade square shape with a cutting blade portion diameter × length of 6 mm × 12 mm and a twist angle of 30 degrees by grinding. Were manufactured respectively.
Next, the above-mentioned tool base 11 (end mill) 1 to 4 is subjected to the same steps as steps (a) to (e) of Example 1 using the AIP apparatus 10, and the surface-coated end mill of the present invention shown in Table 9 is used. 11 to 18 (hereinafter referred to as the present invention tools 11 to 18) were produced.
For the inventive tools 11 to 18 produced above, the identification of the lower W layer, metal carbide layer and metal carbonitride layer and the thickness of each layer were calculated in the same manner as in Example 1. Also in the upper layer A layer and B layer, the average composition and average layer thickness of each component were calculated.
Table 9 shows the measured and calculated values.

Next, with respect to the end mills of the above-described tools 11 to 18 of the present invention, a side cutting test of a Ni-based heat-resistant alloy was performed under the following conditions (referred to as cutting condition 2), and the flank wear width of the cutting edge was measured.
<Cutting condition 2>
Workpiece-Plate material of Ni-based heat-resistant alloy (Cr 19 mass%-Fe19 mass%-Mo3 mass%-Ti0.9 mass%-Al0.5 mass%-Ni balance) with plane dimensions: 100 mm x 250 mm and thickness: 50 mm ,
Cutting speed: 40 m / min,
Rotational speed: 2100 min. ^-1 ,
Cutting depth: ae 0.3 mm, ap 6 mm,
Feed rate (per blade): 0.03 mm / tooth
Cutting length: 10 m,
Table 10 shows the cutting test results.

Example 3
Using the round bar sintered body having a diameter of 10 mm manufactured in Example 2 above, from this round bar sintered body, the diameter x length of the groove forming part is 6 mm x 30 mm, and by grinding, A tool base 11 (drill) made of a WC-base cemented carbide having a two-blade shape with a twist angle of 30 degrees was manufactured.

Next, honing was applied to the cutting edge of the tool base 11 (drill), ultrasonic cleaning was performed in acetone, and drying was performed.
Next, the surface-coated drills 21 to 28 of the present invention (hereinafter referred to as the present invention tools 21 to 28) provided with the lower layer and the upper layer shown in Table 11 under the same conditions as in Example 1 were charged into the AIP apparatus 10. Manufactured).

For the inventive tools 21 to 28 produced as described above, the identification of the lower W layer 4, the metal carbide layer 5 and the metal carbonitride layer 6 and the thickness of each layer were calculated in the same manner as in Example 1. Also in the upper layer A layer and B layer, the average composition and average layer thickness of each component were calculated.
Table 11 shows the measured and calculated values.

Next, with respect to the above-mentioned tools 21 to 28 of the present invention, a wet drilling test of a Ni-base heat-resistant alloy was carried out under the following conditions (referred to as cutting condition 3), and the cutting edge clearance when the number of drilling operations was 30 holes The surface wear width was measured.
<Cutting condition 3>
Workpiece-Plate material of Ni-based heat-resistant alloy (Cr 19 mass%-Fe19 mass%-Mo3 mass%-Ti0.9 mass%-Al0.5 mass%-Ni balance) with plane dimensions: 100 mm x 250 mm and thickness: 50 mm ,
Cutting speed: 13.7 m / min. ,
Feed: 0.06 mm / rev,
Hole depth: 12 mm,
Table 12 shows the cutting test results.

From the results shown in Table 8, Table 10, and Table 12, the tools 1 to 8, 11 to 18, and 21 to 28 of the present invention are accompanied by high heat generation and a large thermal load and mechanical load on the cutting edge. It can be seen that in high-speed cutting of such a Ni-base heat-resistant alloy, no peeling occurs, and no abnormal damage such as welding, chipping or chipping occurs, and excellent wear resistance is exhibited over a long period of use.
On the other hand, the comparative tools 1 to 6 caused peeling, chipping, chipping, etc. due to thermal load and mechanical load acting on the cutting edge, and the life was short.

The coated tool of the present invention suppresses the occurrence of delamination in high-speed cutting of a Ni-base heat-resistant alloy that is accompanied by high heat generation and a large thermal load and mechanical load acts on the cutting edge. It suppresses the occurrence of abnormal damage such as chipping and chipping, and exhibits excellent cutting performance over a long period of use.

2 Lower layer 3 Upper layer 4 W layer (tungsten layer)
5 Metal carbide layer 6 Metal carbonitride layer 10 AIP equipment (arc ion plating equipment)
11 Tool base 12 Rotary table 13 Al-Ti alloy target (evaporation source)
14 Al-Ti-Cr-Si-Y alloy target (evaporation source)
15, 16

Anode electrode

17, 18 Arc power source 19 Bias power source 20 Reactive gas inlet 21 Exhaust gas port

Claims

In a surface-coated cutting tool in which a lower layer is provided on a tool base made of a tungsten carbide base cemented carbide, and an upper layer of an alternately laminated structure is provided on the surface of the lower layer,
(A) The lower layer includes a W layer, a metal carbide layer, and a metal carbonitride layer,
(B) The W layer is formed over a depth of 10 to 500 nm from the surface of the tool base to the inside thereof.
(C) The metal carbide layer is any one metal carbide layer selected from Ti, Cr, Zr, Hf, Nb and Ta, and has an average layer thickness of 5 to 500 nm, Formed directly above,
(D) The metal carbonitride layer is a metal carbonitride layer containing a metal component contained in the metal carbide layer, has an average layer thickness of 5 to 300 nm, and is directly above the metal carbide layer. Formed,
(E) The upper layer has an alternating laminated structure in which at least one layer of A and B layers are alternately laminated, and has a total average layer thickness of 1.0 to 8.0 μm,
(F) The A layer is a composite nitride layer of Al and Ti having a single layer average thickness of 0.1 to 5.0 μm, and its composition is expressed by a composition formula: (Al x Ti 1-x ) N In the case of
Having an average composition satisfying 0.40 ≦ x ≦ 0.70 (where x is an atomic ratio),
(G) The B layer is a composite nitride layer of Al, Ti, Cr, Si, and Y having a single layer average thickness of 0.1 to 5.0 μm, and the composition is expressed by a composition formula: (Al 1 when expressed in -a-b-c-d Ti a Cr b Si c Y d) N, 0 ≦ a ≦ 0.40,0.05 ≦ b ≦ 0.40,0 ≦ c ≦ 0.20,0 A surface-coated cutting tool having an average composition satisfying .01 ≦ d ≦ 0.10 (where a, b, c, and d are atomic ratios).
The surface-coated cutting tool according to claim 1, wherein the surface-coated cutting tool is any one of a surface-coated insert, a surface-coated end mill, and a surface-coated drill.
A surface-coated cutting tool for high-speed Ni-base heat-resistant alloy machining comprising the surface-coated cutting tool according to claim 1 or 2.